Effect of Al addition on low-temperature synthesis of Ti3SiC2 powder

In the present study, Ti/Si/2TiC/xAl (x=0, 0.05, 0.1, 0.15, and 0.2) powder mixtures were heated in vacuum for synthesis of Ti3SiC2 powder. It was found that Al addition accelerated the synthesis reaction for Ti3SiC2. When Al of x=0.2 was added, the synthesis temperature for single-phase Ti3SiC2 was lowered to 1150 degrees C from 1500 degrees C. The mechanism of the accelerating effect of Al addition on Ti3SiC2 formation was revealed to be that molten At plays the role of deoxidation agent, which prompts the synthesis of Ti3SiC2 through accelerating the formation of Ti5Si3 intermediate phase. In addition, equations for quantitative evaluation of the contents of three coexisting phases (Ti3SiC2, Ti5Si3, and TiC) during the synthesis process were derived in this study based on experimental calibration. (c) 2007 Elsevier B.V. All rights reserved.